Stuttering during free rev

[Ravewolf]

As the title states, she pops and stutters when I free rev her. Has done this since day one of when I bought the truck. It doesn't do it under heavy throttle, or when I'm cruising steady,just when it's idling and I rev it.

I figured it was the junk edge tuner, and a new tuner would help. But it still does it, even when warm. It does puff gray smoke when it stutters, but clears up after a few revs. It reminds me of having a car with a carburetor that has a stuck float, you have to rev it because it "loads up". 

What could it be? MAP Sensor? My cel is on but it's from my apps sensor, and I have a new one ordered. Even before when there were no codes it still stuttered like this. 

Could I tune this out on quadzilla? 

 

[kzimmer]

I don't believe the quad will help this situation. This may not be relevant, but if I free rev my truck with heavy throttle mine will studded and blow a bit of white smoke. That's from retarded injection timing due to the low boost high throttle timing retard feature to allow faster turbo spoolup.

[Me78569]

dont free rev, problem solved  

 

the quad wont do much to help this.

[Ravewolf]

34 minutes ago, Me78569 said:

dont free rev, problem solved  

 

the quad wont do much to help this.

Ok.

 

1 hour ago, kzimmer said:

I don't believe the quad will help this situation. This may not be relevant, but if I free rev my truck with heavy throttle mine will studded and blow a bit of white smoke. That's from retarded injection timing due to the low boost high throttle timing retard feature to allow faster turbo spoolup.

So this is normal then? I mean, she runs good otherwise. 

[Me78569]

Depending on the truck and the setup it is pretty normal.   dont worry about it.

[Mopar1973Man]

Timing map mostly. 

[Dieselfuture]

What did I miss,  when was spotter at free reving ok. Something isn't right, could be a Vp, cam/crank sensor, apps, nap, idk, just doesn't seem right. Have you pulled codes with a good scanner. 

[dripley]

Mine has never done that its entire life, even with worn injectors. Miss at idle and under  hard throtle yes but not free reving.

[Ravewolf]

I don't think it's normal. It's a hard sputter. Something isn't right. The only codes I have are the boost code from the quadzilla and the apps sensor code. With the way things are going on this truck, my vp is probably about to die next. It's killed everything else but the front and rear axles. 

My next step is going home on days off, and I'm parking the damn thing until further notice. That's if I don't set fire to it and run it through the home of the guy I bought it from. 

2 hours ago, Dieselfuture said:

What did I miss,  when was spotter at free reving ok. Something isn't right, could be a Vp, cam/crank sensor, apps, nap, idk, just doesn't seem right. Have you pulled codes with a good scanner. 

 

[Dieselfuture]

If you have apps code that could very well be your problem, make sure to use a Timbo sensor. 

[kzimmer]

I definitely don't think it's normal. My point was that the quadzilla likely won't help. When mine does it, it's caused by the quad and how it's set up.

[Mopar1973Man]

Just for verifying. Unhook the Quadzilla completely. (Wire Tap, MAP sensor, and CANBus). Then try again. This just leaves you back to stock ECM.

 

If its still doing it with the Quadzilla then I would look at the injectors and have them verified. 

 

Quadzilla becomes active above 1,000-1,200 RPM's. So then I would have to say that your timing set up is too advanced. I would drop your timing back down again.

 

I will admit a small secret that injector pop pressure does affect the timing you need. Like my 320 bar injectors need way more retarded timing than my worn out 7 x 0.0085 did. This is due to the fact the atomize droplets are much finer and require much less timing to go BANG! When injectors wear out and pop pressure falls below 293 bar now you adding timing because the droplets are larger and take way more time to heat, vaporize, and go BANG!

 

Don't get carried away with timing too much... I know everyone says more timing is better but it based on pop pressure, cetane levels, IAT Temperature, Coolant temperature, etc. 

[Me78569]

The quad will very likely cause popping during free rev is your level is above 1.   The timing map of the quad is not expecting free rev condition.  you would need a good bit of timing during free rev, the lack of load makes it hard to do so.  I never wrote a routine to handle this because it isn't important to fix.    It would need another map and to somehow watch for low load and some throttle.   It would just be messy.

 

Easy fix is just not to free rev.  

 

manual trucks do it way worse than auto trucks given that the weight of the TC makes enough load to not have issues.

Edited February 22, 2019 by Me78569

[Ravewolf]

16 hours ago, Dieselfuture said:

If you have apps code that could very well be your problem, make sure to use a Timbo sensor. 

 

16 hours ago, kzimmer said:

I definitely don't think it's normal. My point was that the quadzilla likely won't help. When mine does it, it's caused by the quad and how it's set up.

 

13 hours ago, Mopar1973Man said:

Just for verifying. Unhook the Quadzilla completely. (Wire Tap, MAP sensor, and CANBus). Then try again. This just leaves you back to stock ECM.

 

If its still doing it with the Quadzilla then I would look at the injectors and have them verified. 

 

Quadzilla becomes active above 1,000-1,200 RPM's. So then I would have to say that your timing set up is too advanced. I would drop your timing back down again.

 

I will admit a small secret that injector pop pressure does affect the timing you need. Like my 320 bar injectors need way more retarded timing than my worn out 7 x 0.0085 did. This is due to the fact the atomize droplets are much finer and require much less timing to go BANG! When injectors wear out and pop pressure falls below 293 bar now you adding timing because the droplets are larger and take way more time to heat, vaporize, and go BANG!

 

Don't get carried away with timing too much... I know everyone says more timing is better but it based on pop pressure, cetane levels, IAT Temperature, Coolant temperature, etc. 

 

5 hours ago, Me78569 said:

The quad will very likely cause popping during free rev is your level is above 1.   The timing map of the quad is not expecting free rev condition.  you would need a good bit of timing during free rev, the lack of load makes it hard to do so.  I never wrote a routine to handle this because it isn't important to fix.    It would need another map and to somehow watch for low load and some throttle.   It would just be messy.

 

Easy fix is just not to free rev.  

 

manual trucks do it way worse than auto trucks given that the weight of the TC makes enough load to not have issues.

Timbo apps is on the way! I'm thinking it's more than likely the quadzilla doing it because I haven't played with the tunes much. She drives beautiful otherwise (messed with the power levels today), and my god the power she has now! Even my turbo seems to spool quicker! 

I'm going to unhook it though tomorrow night and see if the condition still exists. I plan on new injectors as is (I don't trust the previous builder), but I have to make do with the ones I have for now. 

Again, thanks for all the help, I've learned so much here, even in this one post. I'll report back tomorrow what I find. 

[Me78569]

The shuttering will be less as bad,  Nature of the beast.  but nothing is wrong other than the fact that the quadzilla doesn't have free rev maps